Container orchestration in production in Docker - Mini Project: Build & Apply

Container orchestration in production

📖 Scenario: You are working as a DevOps engineer for a small web application team. They want to run their web app using multiple containers to handle more users. You will help them set up a simple container orchestration using Docker Compose to run a web server and a database together.

🎯 Goal: Build a Docker Compose setup that runs a web server container and a database container together. You will create the initial Docker Compose file, add configuration for environment variables, define the services, and finally run the containers to see them working together.

📋 What You'll Learn

Create a Docker Compose YAML file named docker-compose.yml

Define two services: web and db

Set environment variables for the db service

Use official Docker images: nginx:latest for web and mysql:8.0 for db

Expose port 80 on the web service to the host

Run the Docker Compose setup and verify both containers are running

💡 Why This Matters

🌍 Real World

Docker Compose is widely used to run multi-container applications locally or in small production environments. It helps developers and DevOps teams manage related containers easily.

💼 Career

Understanding container orchestration basics with Docker Compose is essential for DevOps roles. It prepares you for more advanced orchestration tools like Kubernetes.

1

Create the initial Docker Compose file

Create a file named docker-compose.yml with the version set to '3.8' and define two services: web and db. For now, set the image for web to nginx:latest and for db to mysql:8.0.

Docker

# Your docker-compose.yml file
version: '3.8'
services:
  web:
    image: nginx:latest
  db:
    image: mysql:8.0

Need a hint?

Use the version key at the top, then define services with web and db each having an image.

2

Add environment variables for the database

In the docker-compose.yml file, add environment variables under the db service: MYSQL_ROOT_PASSWORD set to rootpass and MYSQL_DATABASE set to myappdb.

Docker

version: '3.8'
services:
  web:
    image: nginx:latest
  db:
    image: mysql:8.0
    environment:
      # Add environment variables here

Need a hint?

Use the environment key under db and list the variables with their exact names and values.

3

Expose port 80 on the web service

In the docker-compose.yml file, under the web service, add a ports section that maps port 80 of the container to port 80 on the host machine.

Docker

version: '3.8'
services:
  web:
    image: nginx:latest
    # Add ports mapping here
  db:
    image: mysql:8.0
    environment:
      MYSQL_ROOT_PASSWORD: rootpass
      MYSQL_DATABASE: myappdb

Need a hint?

Use the ports key under web and map the container port 80 to host port 80 using the format "80:80".

4

Run the Docker Compose setup and verify containers

Run the command docker-compose up -d in the terminal to start the containers in detached mode. Then run docker-compose ps to list running containers. Write a print statement that outputs the exact text: Containers web and db are running.

Docker

# Run docker-compose commands in terminal
# Then print confirmation message below
# Your code here

Need a hint?

Use print("Containers web and db are running") to show the final confirmation message.